JPH0739144B2 - Joint structure of hollow synthetic resin - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joining structure of a joining portion in the case where a hollow body is manufactured by abutting and joining an injection-molded half body.

[0002]

Blow molding is generally used as a method for manufacturing a hollow container. However, in consideration of the structural strength or shape of the hollow body, the divided half body is subjected to primary injection molding, and the half body is then injected. A two-step molding method has been proposed in which a resin is abutted against each other and a resin is secondarily injection-molded at the abutting portion (Patent Publication 2).
-20410). However, when the entire hollow body is large and the joints need to have a certain level of joint strength, there is a problem in that it is not sufficient to injection-mold a molten resin for joining the joints.

[0003]

By the way, in the case of manufacturing a hollow body by abutting half-split bodies, in order to give a certain joint strength to the joint portion of the hollow body, the joint surface is perpendicular to the horizontal direction. It is desirable that both joint surfaces engage with each other in different directions, but in order to perform engagement in the vertical direction, a slide structure is attached to the mold to form an engaging portion orthogonal to the mold cutting direction. However, it is necessary to have a structure for retracting the slide core when the die is removed, which causes a problem of complicating the die structure. Therefore, an object of the present invention is to provide a joining structure that provides a joining force with a large joining strength without providing such a slide structure in a mold.

[0004]

According to the present invention, a flange portion having a through hole in a die cutting direction is formed on a joint surface, and a vertical direction engaging force is increased by a molten resin injected so as to connect the through hole. It was made paying attention to the fact that it can be done, and the injection-molded halves are abutted against each other in their respective molds, and a molten resin material for joining is injected into the abutting portions for joining. In the structure, each of the abutting end faces of each half body is formed with a flange portion facing each other at a constant interval, and through holes are intermittently formed in the die cutting direction in the longitudinal direction on both the flange portions, Joining of synthetic resin hollow bodies characterized in that the molten resin is injected into a meandering space formed by the through holes of both flanges in the end face abutting state of each half-split body. In structure.

[0005]

According to the present invention, since the abutting end surface is provided with the flange portion having the through hole in the longitudinal direction intermittently forming the through hole in the die cutting direction, it can be formed without attaching the slide structure to the die.
Moreover, since the through holes of the opposing flanges form a meandering continuous void, the molten resin injected into the void not only has a large contact area with the joint end surface, but also from the through hole to the back surface. Therefore, the anchor effect can be exerted and a strong joint strength can be obtained. (See Figure 7).

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to specific examples shown in the accompanying drawings. FIG. 1 is a cross-sectional view showing a molding state of the joint structure of the present invention, showing a state before mold clamping for secondary molding after primary molding of each half body of the hollow body.
2 is an enlarged perspective view of an essential part thereof, FIG. 3 is a sectional view showing a state where molten resin is injected into the joint structure of the present invention after mold clamping for secondary molding, and FIG. 4 is an enlarged perspective view of the essential part. Is.

In the drawings, 1 is an upper mold, 2 is a lower mold, and hollow halves 3 and 4 are formed in each. The half-split body 3 has flange portions 31 and 32 protruding outward from a slightly elevated position on the peripheral edge of the abutting end surface of the main body portion 30, and the flange surface is intermittently die-cut along the longitudinal direction. A plurality of through holes 33 in the direction are formed. On the other hand, the half-split body 4 also has flange portions 41 and 42 projecting outward at a slightly lowered position on the periphery of the abutting end surface of the main body portion 40, and the flange surface does not correspond to the through hole 33. Through holes 43 are intermittently formed in the longitudinal direction.

The through holes 33, 43 are preferably formed over the entire length of the peripheral edge of the half body (see FIG. 2). The through holes 33 and 43 formed in the flange surface are the half-split bodies 3.
In the abutting state of 4 and 4, as shown in FIG. 4 and FIG. 6, a void R1 which is continuous in the longitudinal direction and which is bent vertically is formed, so that the molten resin is inserted into the bent void R1 via the spool. When B is injected, the flange portions 31, 32 and 41, 42 have the joining force of the molten resin exerted on the joining end faces of the peripheral portions of the half halves 3 and 4 over the joining area enlarged by the through holes 33 and 43. Moreover, through hole 3
As shown in FIG. 7, the molten resin B that has spread to the outer surface of the flange portion through the flanges 3, 43 and 4 is
Since it captures 1, 42, it exerts an anchoring effect and engages both halves 3 and 4 in the vertical direction.

Although the curved void path R1 is formed by vertically penetrating holes at positions not facing each other, as shown in FIG. 8, the through holes 34 of the upper flange portions 31, 32 are formed.
Alternatively, the through holes 44 of the lower flange portions 41 and 42 may be diagonally opposed to each other and communicate with each other so that the upper and lower flange portions simultaneously exhibit the anchor effect. Further, as shown in FIG. 9, inner through holes 35 and 45 that do not face each other and through holes 36 and 46 that face each other may be formed to exert an anchor effect.

[0010]

As is apparent from the above description, according to the present invention, a molten resin for joining injection-molded halves to their abutting portions by abutting their end faces against each other in a mold. In a structure in which a material is injected and joined, a plurality of through holes penetrating in the die-cutting direction are intermittently formed along the longitudinal direction of the flange portion in the joining end surface of each half body to form a bent space. Therefore, molding can be performed without attaching a slide structure. In addition, when molten resin is injected into the bent space in the abutting state, the contact area with the flange to be joined is enlarged due to the space, and the molten resin that goes outside the flange through the through hole is vertical. Since the directional engaging force is exerted, a strong joint strength can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a molded state of a joint structure of the present invention,

FIG. 2 is an enlarged perspective view of a main part of FIG.

FIG. 3 is a cross-sectional view showing a state where molten resin is injected into the joint structure of the present invention,

FIG. 4 is an enlarged perspective view of an essential part of FIG.

5 is a sectional view taken along line VV of FIG. 4,

6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 is an enlarged view of a main part of FIG.

FIG. 8 is a sectional view of a second modified example of the joining structure according to the present invention, which corresponds to FIG.

FIG. 9 is a sectional view of a second modified example of the joining structure of the present invention, which corresponds to FIG.

[Explanation of symbols]

1 is an upper mold, 2 is a lower mold, 3 and 4 are hollow halves, 3
0 and 40 are main body parts, 31, 32 are flange parts, 33
Is a through hole, 41 and 42 are flanges, 43 is a through hole, R
1 is a curved empty road.

Continuation of front page (56) References JP-A-63-237917 (JP, A) JP-A-4-175118 (JP, A)

Claims (1)

[Claims] 1. A structure in which end faces of injection-molded halves are abutted against each other in a mold and a molten resin material for joining is injected into the abutting portions to join the halves. The abutting end faces are formed with flange portions facing each other at a constant interval, and through-holes are intermittently formed in the longitudinal direction in the die-cutting direction on both flange portions to abut the end face abutting of each half body. A joint structure for a hollow body made of synthetic resin, characterized in that the molten resin is formed in a meandering space formed by the through holes of both flange portions in this state.